Moving from 1С/BAS to Xero

Move from 1С/BAS to Xero in stages: customers, suppliers, goods and services, open invoices and opening balances go across, and the books stay in order while both systems run in parallel

Xero suits companies that want simple cloud accounting, often with a business or clients abroad, and do not want to keep a heavy 1С/BAS for it. 1С/BAS is also on the official prohibited software list. The worry is the books: that open invoices, advances and account balances will not match after the move. We move you in stages: first we look at what is really in 1С/BAS and clean it, then make a trial load, run both systems in parallel and reconcile with the accountant on one date. 1С/BAS is switched off only after that. Below: what we carry over, how the move goes and which capabilities of Xero we rely on.

Request an integration System page: 1С/BAS →System page: Xero →

What we move

1С/BAS → XeroCounterparties from 1С/BAS — companies and individuals with tax code, addresses, contact people and bank details — become contacts in Xero; duplicates are merged before the load.
1С/BAS → XeroThe list of goods and services you sell and buy is carried over with names and codes, so invoices in Xero are made from the same list.
1С/BAS → XeroUnpaid customer invoices on the switch-over date move as open invoices, so reminders and incoming payments go on from Xero.
1С/BAS → XeroUnpaid supplier bills on the same date move as open bills, so nothing is paid twice or forgotten.
1С/BAS → XeroAdvances received, overpayments and credit notes are carried over separately, so the client's balance in Xero is the same as in 1С/BAS.
1С/BAS → XeroAccount balances on the switch-over date are entered as opening balances, and sales history for the period you choose is loaded as past invoices.

How the move goes

In Xero the owner connects the exchange app to the organisation and confirms its access; Xero has no simple access keys, so this step is done together.
We look at what is really in your 1С/BAS: which catalogues and documents are in use, what is outdated, where data is kept in unusual places; together we decide what moves to Xero and what stays in the archive.
Before the move we clean the data: merge duplicate counterparties and items, fix tax codes and units, and mark old records the new system does not need.
We make a trial load into a test copy of Xero, and your people check customers, products and balances on familiar examples before anything touches the working system.
For the transition both systems run in parallel: new work is done in Xero, and 1С/BAS stays at hand as a reference, so shipments and payments do not stop.
We reconcile together with your accountant: balances, debts and stock in Xero against 1С/BAS on the same date; every difference is explained before the next step.
Only after the reconciliation is 1С/BAS switched off for daily work; its database is kept as an archive for audits and old questions.

Automation scenarios

One client, several cards

Before the same client sits in 1С/BAS under several spellings, and his debt is split between the cards.

After duplicates are merged before the move, and in Xero the client has one card with the whole debt.

Who still owes

Before after a move nobody is sure which invoices were paid before it, and reminders go to clients who have already paid.

After open debts are moved on one date and reconciled with the accountant, so reminders go only to those who really owe.

Advances that disappeared

Before after a move the client's advance is lost, and he gets an invoice for the full amount he has already partly paid.

After advances and overpayments move as separate items, and the first invoice in Xero already takes them into account.

How it works technically

For those who want to check: each point links to the official documentation page it comes from.

BAS products are on Ukraine's official list of prohibited software (Cabinet resolution №1335 of 22.10.2025, based on Presidential Decree №601/2024 of 02.09.2024). The direct ban applies to the state sector, critical infrastructure and systems processing state information resources.
Source: impactalaw.com ↗ checked 2026-09-25
According to the same documentation, the platform automatically builds a REST interface using the OData protocol, through which outside systems can read, change, create and delete data over HTTP.
Source: its.bas-soft.eu ↗ checked 2026-09-25
Xero's API works with all Xero plans, but not every feature is available on every plan: the Payroll API requires a Payroll plan.
Source: developer.xero.com ↗ checked 2026-09-25
Access goes through OAuth 2.0 with a registered app; Xero has no simple API keys.
Source: developer.xero.com ↗ checked 2026-09-25
Per connected organisation: up to 5 calls at once, 60 calls a minute and 5,000 calls a day.
Source: developer.xero.com ↗ checked 2026-09-25
Xero notifies connected apps about some events itself; in 2026 it added notifications for credit notes, prepayments and overpayments.
Source: developer.xero.com ↗ checked 2026-09-25

Limits

The limits come from both systems. Xero caps the number of requests for each connected organisation per minute and per day, so a long sales history is loaded in portions over several passes; we plan the load around it. Payroll data in Xero needs a plan with payroll, so by default we do not move it. Warehouse accounting from 1С/BAS is not part of this move: if you need it, we decide where it lives at the audit. 1С/BAS is on the official prohibited software list: we do not take projects for state bodies, critical infrastructure or systems with state data, and with private businesses we discuss the risk openly.

How to start

Three steps from a first message to work on your project.

01
Leave a request
Describe the task in the form — in text or by voice. Budget and timing are optional.
02
We review and estimate
A developer studies the brief, asks about anything unclear and sends an estimate.
03
We start
Once scope and price are agreed, the work begins.

Leave a request

or write to info@coreviaflow.space

Live project We built and run Gemalli — a B2B export platform with producer pages, a CRM and a deal chat. Read the case →

Questions

Is it legal to stay on 1С/BAS?

1С/BAS is on the official prohibited software list. The direct ban covers the state sector, critical infrastructure and systems with state data. For a private business it is formally allowed but considered a risk — check with your lawyer.

Will work stop during the move?

No. For the transition both systems run in parallel: new documents go into Xero, and 1С/BAS stays as a reference until the reconciliation shows the same figures. 1С/BAS is switched off only after that.

What happens to the history and the archive?

The history you need every day — what each client bought, who owes what — moves to Xero. The full 1С/BAS database is kept as an archive, so an old document can still be found for an audit or a dispute.

Can payroll move to Xero too?

Payroll in Xero needs a plan with payroll. If your plan has it, we discuss it as a separate step; by default we move customers, suppliers, invoices and balances.